I know this is a silly question but I'm not that good with maths so really need help.

I want to add 20% to a number but it doesn't add up right.

for example 20% taken from 1000 is 800 but if i wanted to put 20% back on 800 i always come up with 960.

I just want to make it up to 1000 again. It's because i have different figures i have taken 20% off but need then back to the original.

Sorry for being so thick (Thinking)

May 16th 2010, 07:54 AM

matheagle

Most people don't know that if a stock goes down 50% then up 50% you're not back to where you started.
I'm not sure what your exact question is.
But if you decrease your initial amount by 20% you need to increase by 25% to get back to where you started.

May 16th 2010, 08:08 AM

Soroban

Hello, shaun7996!

Quote:

For example: 20% taken from 1000 is 800,
but if i wanted to put 20% back on 800, i always come up with 960.. . Yes, this true.

I just want to make it up to 1000 again.
i have taken 20% off, but need then back to the original.

If is the percentage of paycut, to restore your salary,. . your raise must be: . percent.

Example: a 20% paycut.
To restore your salary, you need a: . raise.

Example: a 25% paycut.
You need a: . raise.

Take a more extreme case: your boss asks you to work at half-pay this month.. . So you take 50% paycut.
To restore your salary, your boss must double your salary . . . a 100% raise.

Get the idea?

May 16th 2010, 08:36 AM

shaun7996

yes i do and thanks alot for your detailed answer, very appreciated.

May 16th 2010, 09:26 AM

matheagle

And it doesn't matter which happens first.
If something increases by 25% and then decreases by 20%
you're back to where you started.
This always fools a lot of investors.
I've seen funds that jump 40 percent after they were down 80 percent.
They're still way way down.
That happened to a lot of funds after the Tech crash.
The Nasdaq is still down 60% from its high of 2001.
And lets not even go near the Nikkei.
That's way worse, and unfortunately where the US is heading. (Worried)